Migrate test files from `as` type assertions to @total-typescript/shoehorn. Use when user mentions shoehorn, wants to replace `as` in tests, or needs partial test data.
shoehorn lets you pass partial data in tests while keeping TypeScript happy. It replaces as assertions with type-safe alternatives.
Test code only. Never use shoehorn in production code.
Problems with as in tests:
as unknown as Type) for intentionally wrong datanpm i @total-typescript/shoehorn
Before:
type Request = {
body: { id: string };
headers: Record<string, string>;
cookies: Record<string, string>;
// ...20 more properties
};
it("gets user by id", () => {
// Only care about body.id but must fake entire Request
getUser({
body: { id: "123" },
headers: {},
cookies: {},
// ...fake all 20 properties
});
});
After:
import { fromPartial } from "@total-typescript/shoehorn";
it("gets user by id", () => {
getUser(
fromPartial({
body: { id: "123" },
}),
);
});
as Type → fromPartial()Before:
getUser({ body: { id: "123" } } as Request);
After:
import { fromPartial } from "@total-typescript/shoehorn";
getUser(fromPartial({ body: { id: "123" } }));
as unknown as Type → fromAny()Before:
getUser({ body: { id: 123 } } as unknown as Request); // wrong type on purpose
After:
import { fromAny } from "@total-typescript/shoehorn";
getUser(fromAny({ body: { id: 123 } }));
| Function | Use case |
|---|---|
fromPartial() | Pass partial data that still type-checks |
fromAny() | Pass intentionally wrong data (keeps autocomplete) |
fromExact() | Force full object (swap with fromPartial later) |
Gather requirements - ask user:
as assertions causing problems?Install and migrate:
npm i @total-typescript/shoehornas assertions: grep -r " as [A-Z]" --include="*.test.ts" --include="*.spec.ts"as Type with fromPartial()as unknown as Type with fromAny()@total-typescript/shoehorn